Certain services are designed with the assumption that there will be only one active instance of each service running in a cluster at any given time. Examples of such services include transaction managers, JMS backends, and administration services. In order to enable these services to survive server failures or other problems, a mechanism can be used to move each service from a failed server to a healthy server in the cluster. A problem arises, however, in ensuring that each and every service is never active on more than one server at a time. Another problem, which is common with many distributed systems, involves how to ensure that all servers in the cluster agree to the new server.